The Casio Exilim EX-Z850 is a full-featured and well-built ultra-compact digital camera. A rare thing among such small cameras, the Z850 features manual controls over shutter speeds up to 60 seconds and a choice of 2 apertures at all focal lengths. Overall, the Z850 is a pleasing camera with accurate colors, good white-balance, speedy operation and great battery life. Its main problem is a tendency to overexpose outdoor shots with a bright background. This can be easily compensated by using negative exposure compensation but this removes the Z850 from the list of foolproof cameras. Other negatives of this camera occur in limit conditions such has high image-noise in low-light and color-shift near overexposed areas. Even though the Z850 shows great battery-life at 440 shots-per-charge, the battery must inconveniently be recharged in the camera while attached to its docking station.

Compared to most other ultra-compact digital cameras, the Z850 packs more controls and features. Other ultra-compact cameras with manual controls include mostly other Casio models such as the Z750 and Z120. The Z120 has the notable distinction of being the only ultra-comact with manual controls which runs on AA batteries. Since the Z850 performs better than these two models in most areas, particularly image quality, the Casio Z850 is recommended for manual controls in an ultra-compact. Still, the now discontinued Fuji Finepix F810, which has better image quality and full manual controls but poor battery life, may still be obtained for a good price.

Forgetting about manual controls, there are quite a few excellent ultra-compact cameras which perform better and more reliably. The Fuji Finepix F30 and Fuji Finepix F10 both have vastly superior image quality and longer battery life, combined with excellent speed, useable high-ISO sensitivities and a powerful flash. Although the 7 Megapixels Canon Powershot SD550 does not match the Fuji F30's or F10's image quality, it does better than the Z850 and is as foolproof as it gets for a point-and-shoot camera.